15KISP mg2+ ION drive

[PB666]

http://honisoit.com/2015/09/university-of-sydney-student-smashes-nasa-record-for-fuel-efficiency-mars-and-back-on-a-tank-of-fuel/

Pure magnesium is a solid with a considerably higher density than xenon and in zero atm does not need to be contained, but how to atomize the magnesium before ionization? They claim its is arched by electric current and then focused into the propulsion accelerator.

Anyway Vasimr is higher.

Edited September 18, 2015 by PB666

[passinglurker]

Anyway Vasimr is higher.

Anyway this just sounds like a Pulsed Plasma Thruster that uses magnesium instead of teflon. the whole deal just seems like click bait to me.

[Streetwind]

This is pretty much a PPT, yes.

But, passinglurker: Do you realize that a classic teflon PPT achieves 1,300s worth of specific impulse, and this one does 14,700s with magnesium? That's a pretty hardcore step up. PPTs were always considered a bit of a disappointing technology, useful maybe as cheap throwaway RCS thrusters on geostationary satellites. This one actually has the makings of a proper engine.

Of course, this article is, in typical online journalism fashion, producing a lot of text and "could be"'s out of very little hard data. Specific impulse isn't everything. ESA developed and tested a 19,300s, 2.5 N, 250 kW ion thruster in 2003 and then promptly shelved it because there's simply no practical application. There's no power source to drive it, and the Isp is actually too high to make sense for commercial satellites. Sounds funny, but there's a curve for ideal electric engine Isp depending on power source, payload mass and mission dV - and we're currently around 3,000s - 6,000s for the technology we have and the missions we want to fly. That's why the VASIMR is targeting an Isp of 5,000s in its reference implementation; going higher is pointless from a market demand standpoint.

What the article doesn't tell you is the other performance figures of the novel thruster. The HiPEP it cites for comparison does 9600s, 0.67 N, 40 kW. And this new one does 14,700s, less than 0.67 N, unknown kW. High Isp is easy to achieve with a lot of power input, because the more power you throw at the problem, the worse the engine scales in thrust. At the high end, it's almost only Isp that scales. So it's entirely possible that this guy may have thrown 100 kW at the problem and recorded a single very high number. This does not make the invention a usable engine though.

I'm still curious for more details though. How the bleep does one get nearly 15k seconds Isp with a bog standard pulsed plasma thruster?! That's ridiculous no matter how you turn it. There has to be something in that engine that differentiates it from a classic PPT, besides the fuel choice. In fact, there MUST be something, or else this isn't going to be viable and just going to be a giant power sink for nearly no thrust. Hope that presentation of the guy at the end of this month is recorded and made available online...

[PB666]

This is pretty much a PPT, yes.

But, passinglurker: Do you realize that a classic teflon PPT achieves 1,300s worth of specific impulse, and this one does 14,700s with magnesium? That's a pretty hardcore step up. PPTs were always considered a bit of a disappointing technology, useful maybe as cheap throwaway RCS thrusters on geostationary satellites. This one actually has the makings of a proper engine.

Of course, this article is, in typical online journalism fashion, producing a lot of text and "could be"'s out of very little hard data. Specific impulse isn't everything. ESA developed and tested a 19,300s, 2.5 N, 250 kW ion thruster in 2003 and then promptly shelved it because there's simply no practical application. There's no power source to drive it, and the Isp is actually too high to make sense for commercial satellites. Sounds funny, but there's a curve for ideal electric engine Isp depending on power source, payload mass and mission dV - and we're currently around 3,000s - 6,000s for the technology we have and the missions we want to fly. That's why the VASIMR is targeting an Isp of 5,000s in its reference implementation; going higher is pointless from a market demand standpoint.

What the article doesn't tell you is the other performance figures of the novel thruster. The HiPEP it cites for comparison does 9600s, 0.67 N, 40 kW. And this new one does 14,700s, less than 0.67 N, unknown kW. High Isp is easy to achieve with a lot of power input, because the more power you throw at the problem, the worse the engine scales in thrust. At the high end, it's almost only Isp that scales. So it's entirely possible that this guy may have thrown 100 kW at the problem and recorded a single very high number. This does not make the invention a usable engine though.

I'm still curious for more details though. How the bleep does one get nearly 15k seconds Isp with a bog standard pulsed plasma thruster?! That's ridiculous no matter how you turn it. There has to be something in that engine that differentiates it from a classic PPT, besides the fuel choice. In fact, there MUST be something, or else this isn't going to be viable and just going to be a giant power sink for nearly no thrust. Hope that presentation of the guy at the end of this month is recorded and made available online...

Hmmm, magmesium is stable as 2+ and has a aw of 24.3, if we go by that the charge to mass ratio is 0.08 while Xenon is 0.008 for the first electron, etc, so you would have to strip 10 Xenon electrons to have the same ability to accelerate as fast as Xenon. The reason its a waste is the magnesiun ~3.5 more momentum but 10 times as much energy. This problem can be overcome only if the an equvilent reduction if a 3.5 fold lower solar power weight. More so in mars orbect. The problem with xenon is that it has proportionally more neutrons and is harder to remove its inner most electrons relative to magnesiums inner shell neutrons.

We'll it looks like we don't need a massive VASIMR, bad for them, we need much more power to weight generators. Mg is lower aw than argon and is much much easier to store in space.

[Red Dwarf]

It works the same way as an ion engine, but apparently it can use titanium, aluminum, and magnesium instead of xenon. http://www.iflscience.com/technology/mars-and-back-one-tank-magnesium

[Bill Phil]

Using metals for propellant? Awesome!

[passinglurker]

*sigh* second article/thread on this and still all they flout is max isp and nothing about the thrust or the performance of other materials besides "they get more thrust and less isp". how much more!? how much less!? what is the kraken damned ratio!?

Seriously every time someone claims to come up with a "new space engine" the worst articles comes out of the woodwork.

[UmbralRaptor]

I would like to point out that some early prototype ion engines used mercury as a propellant. Though the description of the drive (vaporizing solid fuel with bursts of electricity) makes it sound sort of like a pulsed plasma thruster.

As for the drive itself, the creator appears to have a blog: http://www.neumannspace.com/

Hopefully the conference will publish abstracts?

[Streetwind]

We already have a thread on this too, even still on the first page of this forum: http://forum.kerbalspaceprogram.com/threads/134540-15KISP-mg2-ION-drive

You can read my comments in there.

[sal_vager]

Thought I'd better merge these.

[PB666]

I think many of you are missing the point. There are two problems with gaseous propellants.

1. pressurization, it is difficult without liquification to reach maximum density.

2. those containeres are often shaped in ways that are difficult to pack.

You can literally pack aluminum or magnesium in solid blocks, magnesium needs a thin skin of reductant to protect it for oxygen. The other thing, what are you going to be getting lots of in space. The best sources of argon are in the celestials of jupiter and saturn. There is no good source of xenon.

None of the stony asteroids contain alot of water, but the stoney asteroids are rich in magnesium silicates. You are not going to find alot of water rich asteroids inside the asteroid belts orbital radius, and the c-rich asteroids have neither a goo source of hydrogen for making hydrocarbons or oxygen for making oxidant. If oxygen is desired it will have to be split off of silicon oxides.

[Streetwind]

You are not going to find alot of water rich asteroids inside the asteroid belts orbital radius, and the c-rich asteroids have neither a goo source of hydrogen for making hydrocarbons or oxygen for making oxidant. If oxygen is desired it will have to be split off of silicon oxides.

There are very large amounts of water even in near Earth objects - hundreds to thousands of metric tons per object. Water is the first thing that will be sought out for mining by companies like Planetary Resources and Deep Space Industries.

[wumpus]

The best sources of argon are in the celestials of jupiter and saturn. There is no good source of xenon.

There is more argon in Earth's atmosphere than carbon dioxide. For vessels that need more mass in quantities inconvenient for xenon (presumably a significant fraction of current production), Earth produced argon will be ideal for a long, long, time.

Anybody have any numbers on efficiency or complexity? If the complexity is low (and efficiency somewhat good) it might be good for stationkeeping. If the efficiency is good, there might be some point at which the extra solar panels/RTG equipment/heat sinks might weigh less than extra xenon/argon (I'd be fairly shocked if it won before argon replaced xenon). Every time I hear how "impossible" it would be for new horizons to stop at Pluto, I just thought how nobody wanted to bet their careers (again) on the [then] unproven ion-thruster technology. Leaving a probe in orbit of Pluto sounds about the most extreme condition for a space engine, and might be a good benchmark to divide between "useless for intra-steller flight" and "possible to consider for intra-steller flight".

[PB666]

There is more argon in Earth's atmosphere than carbon dioxide. For vessels that need more mass in quantities inconvenient for xenon (presumably a significant fraction of current production), Earth produced argon will be ideal for a long, long, time.

Anybody have any numbers on efficiency or complexity? If the complexity is low (and efficiency somewhat good) it might be good for stationkeeping. If the efficiency is good, there might be some point at which the extra solar panels/RTG equipment/heat sinks might weigh less than extra xenon/argon (I'd be fairly shocked if it won before argon replaced xenon). Every time I hear how "impossible" it would be for new horizons to stop at Pluto, I just thought how nobody wanted to bet their careers (again) on the [then] unproven ion-thruster technology. Leaving a probe in orbit of Pluto sounds about the most extreme condition for a space engine, and might be a good benchmark to divide between "useless for intra-steller flight" and "possible to consider for intra-steller flight".

Xenon is better because is can be package at higher mass densities than argon. Argon is used in VASIMR. But in principle your response does not deal with the supposition, mining fuel in space, by definition earths argon containing atmosphere layers are not space, its earth bound as to separated from everything else we call space.

[wumpus]

Xenon is better because is can be package at higher mass densities than argon. Argon is used in VASIMR. But in principle your response does not deal with the supposition, mining fuel in space, by definition earths argon containing atmosphere layers are not space, its earth bound as to separated from everything else we call space.

Except that you were arguing "mining" planets that are in a gravity well of 30km/s and 45km/s (vs. Earth's ~10km/s). Since you aren't using Argon (or Xenon) as a propellant to achieve any of those deltaVs, you might as well come back to Earth for it (which already has the infrastructure).

I can't imagine how many decades we are from mining space. The idea of mining The absolutely hardest places in the solar system to get things back from just boggles the mind even further (Pluto would be at least 5 times easier). Have you considered trying a wonderful game called KSP?

[lajoswinkler]

I'd rather ionize and throw out mercury ions than magnesium. It's already liquid so there's no need for spending energy on melting the damn thing. It's also a pretty damn heavy ion, which is a good thing.

Edited September 24, 2015 by lajoswinkler

[PB666]

Except that you were arguing "mining" planets that are in a gravity well of 30km/s and 45km/s (vs. Earth's ~10km/s). Since you aren't using Argon (or Xenon) as a propellant to achieve any of those deltaVs, you might as well come back to Earth for it (which already has the infrastructure).

I can't imagine how many decades we are from mining space. The idea of mining The absolutely hardest places in the solar system to get things back from just boggles the mind even further (Pluto would be at least 5 times easier). Have you considered trying a wonderful game called KSP?

Magnesium as i have pointed out several times is a major component of S asteroids, songravity is no the problem transfering to and stabilizing S asteroids is the problem, pay attention and keep up with the discussion.